meson: stop looking for 'sphinx-build-3'

Once upon a time, "sphinx-build" on certain RPM platforms invoked
specifically a Python 2.x version, while "sphinx-build-3" was a distro
shim for the Python 3.x version.

These days, none of our supported platforms utilize a 2.x version, and
those that still have 'sphinx-build-3' make it a symbolic link to
'sphinx-build'.  Not searching for 'sphinx-build-3' will prefer
pip/venv installed versions of sphinx if they're available.

This adds an extremely convenient ability to test document building
ability in QEMU across multiple versions of Sphinx for the purposes of
compatibility testing.

Signed-off-by: John Snow <jsnow@redhat.com>
Message-Id: <20230221012456.2607692-6-jsnow@redhat.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>

docs/meson.build

@@ -1,10 +1,5 @@
-if get_option('sphinx_build') == ''
-  sphinx_build = find_program(['sphinx-build-3', 'sphinx-build'],
-                              required: get_option('docs'))
-else
-  sphinx_build = find_program(get_option('sphinx_build'),
-                              required: get_option('docs'))
-endif
+sphinx_build = find_program(get_option('sphinx_build'),
+                            required: get_option('docs'))
 
 # Check if tools are available to build documentation.
 build_docs = false

meson_options.txt

@@ -12,7 +12,7 @@ option('pkgversion', type : 'string', value : '',
        description: 'use specified string as sub-version of the package')
 option('smbd', type : 'string', value : '',
        description: 'Path to smbd for slirp networking')
-option('sphinx_build', type : 'string', value : '',
+option('sphinx_build', type : 'string', value : 'sphinx-build',
        description: 'Use specified sphinx-build for building document')
 option('iasl', type : 'string', value : '',
        description: 'Path to ACPI disassembler')

scripts/meson-buildoptions.sh

@@ -55,6 +55,7 @@ meson_options_help() {
   printf "%s\n" '  --localstatedir=VALUE    Localstate data directory [/var/local]'
   printf "%s\n" '  --mandir=VALUE           Manual page directory [share/man]'
   printf "%s\n" '  --sphinx-build=VALUE     Use specified sphinx-build for building document'
+  printf "%s\n" '                           [sphinx-build]'
   printf "%s\n" '  --sysconfdir=VALUE       Sysconf data directory [etc]'
   printf "%s\n" '  --tls-priority=VALUE     Default TLS protocol/cipher priority string'
   printf "%s\n" '                           [NORMAL]'